The radioimmunoasay (RIA) laboratory supports epidemiological (in collaboration with EFSB, NIADDK) and metabolic studies which address the role of islet cell function and insulin resistance in the development and maintenance of obesity and diabetes in the Pima population. RIA's for insulin, C-peptide, glucagon, glucagon-like immunoreactivity (GLI) and somatostatin (SLI) and are performed in conjunction with clinical studies described in reports on projects Z01 AM 69000-17 EFS, Z01 AM 540310-01 DD, Z01 AM 54029-02 DD, and are central to the investigation of islet function and regulation in obesityh and diabetes.